Huge Bill / No Service

I have three contracts with MTN all adding up to around R1200. For the past two months I have received statements from MTN that are more than double that amount, April being R2600 and May being R3500.<br> After visiting a MTN branch in Bloemfontein the consultant showed me that it is for data charges on my cellphone number. I've requested an investigation into this because I haven't used my phone out of the ordinary that my data costs would be more than double my contact for three different services. Half the time I'm connected wirelessly, why else would I have an Internet package? And an iPad package?<br> I have always managed my data usage and when I do run low on data I always buy an extra 1GB. I've always had data available on my phone, why are there extra charges? <br> MTN is making it easy for their customers to move to their competitors and to be honest I don't want to, but if this problem doesn't stop, then I will be forced to.<br> I know there is problems and can't get through to the call centre due to this, but I need someone to get into contact with me to explain. I need answers.